The present invention relates to the field of locking mechanisms. More particularly, this invention relates to a unique lock mechanism that is adaptable to many different locking applications, including but not limited to a trailer hitch security lock.
Various locking mechanisms have been used for trailer hitches. One shortcoming of many of the conventional locking mechanisms for trailer hitches is that they rely on an exposed padlock that can be cut quickly and easily by thieves using bolt cutters. One sharp blow with a hammer and chisel can also pop many padlocks open.
Some trailer hitch locking devices (such as shown by Jackson in U.S. Pat. No. 5,743,549, Nunnick, Jr. et al in U.S. Pat. No. 3,810,664; and Geresy in U.S. Pat. No. 3,226,133) utilize a ball-shaped plug installable in the ball socket of the trailer hitch to prevent thieves from hooking a towing vehicle to the trailer. Unfortunately, these ball-shaped plug locking mechanisms are relatively complex, difficult to manufacture and assemble, and are still not very robust or tamper-proof. For example, the ball-shaped plug of Geresy requires that several bores and an annulus be provided in the ball, along with a securement ring to hold the lock canister in the ball, a pair of curved springs retained between a pair of plates, and screws, etc. The round cross-section of the springs, their natural deformability, and small size makes them relatively easy to break and/or dislodge from the locking recess in the pin. Thus, there is a need for a simpler, more robust key-operated locking mechanism design for a ball-shaped plug lock and other applications.
Therefore, a primary objective of the present invention is the provision of an improved locking mechanism.
Another objective of this invention is the provision of a locking mechanism that has relatively few moving components.
Another objective of this invention is the provision of a locking mechanism that is easy to assemble and install, yet leaves no exposed components that thieves can quickly and easily cut, turn or pry on to open the lock.
Another objective of this invention is the provision of an improved locking mechanism for a trailer hitch security lock.
These and other objectives will be apparent from the drawings, as well as from the description and claims that follow.
The present invention relates to a lock mechanism that is adaptable to many different locking applications, including but not limited to a trailer hitch security lock. The lock mechanism includes a casing having a cavity therein, a shaft with an annular recess insertable into the cavity, a lock tumbler with a rotatable output member, and a spring-biased rigid locking clip pivotally mounted to the casing in the cavity so as to normally engage the recess in the shaft to secure the shaft to the casing unless pivoted out of the recess by the output member of the lock tumbler. A trailer hitch device utilizing this lock mechanism is described in detail herein.